The China Study: Revolutionary Insights On Diet And Disease
The origins of The China Study stem from the early 1970s.
During this time, the premier of China, Chou EnLai, was dying of cancer.
In an attempt to get more insight into the disease, he decided to initiate a national survey of the death rates of twelve kinds of cancer.
880 million people (96% of the population) participated in the survey across 2,400 counties.
It resulted in a cancer atlas of China showing that cancer was a lot more common in certain regions, while there was almost no cancer in other regions.
The data behind the China cancer atlas were profound. The counties with the highest rates of some cancers were more than 100 times greater than counties with the lowest rates of these cancers.
— Dr Campbell (The China Study, page 79)
By contrast, cancer rates in the USA vary a lot less: From one part of the country to another, the cancer prevalence is just two to three times greater.
Even though 87% of the Chinese population at the time was from the same ethnic group, the cancer rates varied tremendously! This suggests that genetics may only play a small role in cancer.
Birth of The China Study
The survey sparked a lot of new questions about the cause of cancer.
Do environmental and lifestyle factors play a role?
The only way to find is to do a large population study.
That opportunity would soon come, in the early 1980s.
By chance, Dr Campbell and Dr. Shen (former deputy director of China’s premier health research laboratory) met each other at the right time.
When we were done we had more than 8,000 statistically significant associations between lifestyle, diet and disease variables.
— Dr Campbell (The China Study, page 73)
The New York Times called The China Study the Grand Prix of Epidemiology!
Diet in Rural China Versus USA
The rural Chinese diet consists mostly of plant-based food, while the American diet contains a large amount of animal-based foods.
One of the initial findings of the China Study was the difference in the average daily dietary intake of rural Chinese and American diets:
Calories: 2641 kcal (China) versus 1989 kcal (USA)
Total fat (% of calories): 14,5% (China) versus 34-38% (USA)
Dietary fiber: 33 gram (China) versus 12 gram (USA)
Protein: 64 gram (China) versus 91 gram (USA)
Animal protein (% of calories): 0,8% (China) versus 10-11% (USA)
Iron: 34mg (China) versus 18mg (USA)
Note: These numbers are standardized for a body weight of 65kg.
To give a couple of examples at the time of our study, the death rate from coronary heart disease was seventeen times higher among American men than rural Chinese men. The American death rate from breast cancer was five times higher than the rural Chinese rate.
— Dr Campbell (The China Study, page 79)
The difference in dietary intake and disease rates between rural China and the USA is enormous.
Taking a closer look at the differences among rural Chinese counties, the researchers noted many more remarkable insights.
Diseases of Affluence Versus Diseases of Poverty
The more economically developed counties had high rates of cancer, diabetes, and heart disease, while the rural agricultural areas had low rates of these chronic diseases. Also known as diseases of affluence or Western diseases.
In general, as people acquire more financial wealth, so do people start consuming more meat, dairy, and fat. Such is the case with the more economically developed counties of China.
On the other hand, infections, parasites, and pneumonia were more common in the less developed rural agricultural areas.
These diseases of poverty were a lot less common in the developed counties of China. In these poorer regions, people consumed a mostly plant-based diet.
So there were two clear groups: Diseases of affluence (more common in developed counties) versus diseases of poverty (more common in rural China).
This provided a nice foundation for researching dietary factors in relation to diseases and disease indicators.
The prevalence of diseases of affluence in economically developed regions versus diseases of poverty in less developed regions was not a new insight.
What made the China Study different is that it also gave us insight into the dietary role in relation to disease.
As mentioned, The China Study had more than 8,000 statistically significant associations between lifestyle, diet and disease variables.
In medical research, there are no certainties, but variables can still be measured in levels of significance.
This way, we can get an insight into how relevant and truthful each variable is.
These are the three levels of statistical significance used in The China Study:
Level I: 95+% certainty
Level II: 99+% certainty
Level III: 99,9+% certainty
In the remainder of this article, we will discuss some of the core variables from The China Study and their statistical significance.
Some variables were below the 95% mark but still high in probability.
One of the strongest indicators of chronic disease was high cholesterol.
This variable has a statistical certainty of 99,9+% (level III), meaning that it is as close to the truth as possible in medical research.
The average cholesterol level in rural China was 127 mg/dL.
Compare that to the average cholesterol level in the USA: 215 mg/dL.
Some counties had average cholesterol levels of 94 mg/dL, while the lowest group average measured was a stunning 80 mg/dL.
As cholesterol levels decreased to 90 mg/dL, so did the following diseases decrease:
- Liver cancer (level II)
- Rectum cancer (level I)
- Colon cancer (level II)
- Lung cancer in males (level I)
- Lung cancer in females
- Breast cancer
- Childhood leukemia
- Adult leukemia (level I)
- Childhood brain cancer
- Adult brain cancer (level I)
- Stomach cancer
- Esophagus cancer
Usually, high cholesterol is associated with heart disease, but The China Study also showed some significant relations between low cholesterol levels and decreased cancer.
Not surprisingly, heart disease rates were very low:
During a three-year observation period (1973-1975), there was not one single person who died of coronary heart disease before the age of sixty-four, among 246,000 men in a Guizhou county and 181,000 women in a Sichuan county!
— Dr Campbell (The China Study, page 79)
According to Dr. Esselstyn, the heart-attack proof cholesterol level is below 150 mg/dL.
Next was to find out which foods affect cholesterol. The following foods and nutrients were associated with increased cholesterol levels:
- Meat (level I)
- Fish (level I-II)
- Fat (level I)
- Animal protein
These are some of the foods and nutrients that were associated with decreased cholesterol levels:
- Plant protein (level I)
- Fiber (level II)
- Soluble carbohydrates (level II)
- B-vitamins from plants (level I)
- Lentils and beans
- Carrots and potatoes
In brief, animal-based foods were correlated with increasing blood cholesterol. With almost no exceptions, nutrients from plant-based foods were associated with decreasing levels of blood cholesterol.
— Dr Campbell (The China Study, page 80)
The average animal protein intake in rural China was 7,1 grams per day, compared to 70 grams per day for the average American.
The China Study gave highly significant insights into the association between animal protein intake among men and increasing levels of cholesterol (level III = 99,9+% certainty)!
On the other hand, plant protein intake was associated with decreased levels of cholesterol (level II).
Other significant animal protein correlations:
- Animal protein intake was highly linked to cancer (level III)
- All animal protein-related blood biomarkers were associated with cancer (level II-III)
- Animal protein intake was associated with taller and heavier people (level I)
- Intake of animal protein was associated with higher levels of cholesterol (level I)
- Animal protein intake was associated with higher body weight (level I)
- Higher body weight and animal protein intake were associated with more cancer (level II-III)
- Higher body weight and animal protein intake were associated with more coronary heart disease (level II)
- Increased plant protein intake was positively associated with greater height and body weight for childhood growth (level II)
Fat is found almost mainly in animal foods.
As we have seen before, average fat intake in rural China (14,5% of total calories) is a lot lower than the average fat intake in the USA (34-38% of total calories).
The China Study found that:
Increased intake of fat was associated with increased cholesterol (level I)
Increased fat/increased cholesterol was associated with more breast cancer (level I)
Increased fat/increased cholesterol was associated with menarche at an earlier age (level I)
Fiber is only found in plant foods, predominantly beans, whole grains, and leafy vegetables.
The average intake of fiber in rural China was 33,3 grams per day, compared to 11,1 grams per day in the USA.
These are some of the variables found in The China Study:
- High-fiber intake was associated with lower rates of rectum and colon cancer
- High-fiber intake was associated with lower levels of cholesterol (level I-II)
- The higher the intake of dietary fiber, the higher the level of iron in the blood (level I)
Antioxidants are found almost exclusively in plants.
Antioxidant levels were recorded by measuring the intake and blood levels of vitamin C.
With this information, some striking correlations were made, including:
- In people with low levels of vitamin C in the blood, there was a bigger probability of higher prevalence of cancer (level III)
- Low vitamin C levels were associated with a higher risk for esophageal cancer (level III)
- Low vitamin C levels were associated with a higher risk for leukemia, nasopharynx, breast, stomach, liver, rectum, colon and lung cancer
- Cancer, coronary heart disease and hypertensive heart disease rates were five to eight times higher in areas where fruit consumption was the lowest
- Stroke rates were five to eight times higher in areas where fruit consumption was the lowest (level II)
The China Study warns not to consume vitamin C in supplement form:
The triumph of health lies not in the individual nutrients, but in the whole foods that contain those nutrients: plant-based foods..
— Dr Campbell (The China Study, page 94)
The China Study: Conclusions
The statistically significant variables we’ve mentioned are only a small portion of the total amount of significant insights (8,000+).
All these associations combined appear to paint a clear picture: A Whole Food Plant Based diet offers optimal health benefits!
What are the odds that all of these associations (and many others) favoring a plant-based diet are due to pure chance? It is extremely unlikely, to say the least. Such consistency of evidence across a broad range of associations is rare in scientific research. It points to a new worldview, a new paradigm. It defies the status quo, promises new health benefits and demands our attention.
— Dr Campbell (The China Study, page 103)
Want to read about the other insights of the China Study? Purchase The China Study book and specifically read through pages 69-108. In this article, we’ve attempted to provide you with a general overview of the China Study. Also, take a look at Dr. Campbell’s cancer in rats studies. The insight of that research led him to the China Study. Both studies point in the same direction: The more whole plant foods, the better.
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